Interest in gray-water systems shot up immediately after
California Governor Jerry Brown announced on April 1 a mandatory 25-percent
reduction in water use by cities and towns in the state, AP
reported.

"There's huge interest," Laura Allen, a co-founder of
Greywater Action, a proponent of household water recycling, told
AP. Contractors "told us they're getting so many more calls
than before," she added.

The state has in recent years modified its plumbing codes and
laws on the use of gray water, or non-potable runoff from
household water sources that do not include pathogenic "black
water" from toilets, which must be sent to wastewater
treatment plants.

Californians are now allowed to install safe gray-water systems
without a permit. The systems can irrigate with untreated water
from bathroom sinks, washing machines and showers, but only if
the water runs underground beneath soil or mulch. The untreated
water must not come into direct contact with people or food. For
example, untreated gray water could be used on tomato plants but
not to root vegetables.

Some systems treat gray water for wider use. Water Recycling
Systems of Redondo Beach, California says its
process "filters and disinfects that water so it can be
safely re-used for landscape irrigation and other permitted
uses."

California Building Industry Association executive Robert Raymer
told AP there are numerous companies that are promoting in-home
water recycling services. But not all approaches are the same.

"Just like there's no one sure way to fight the drought,
there's no one sure way for gray-water treatment," he said.
"Everybody has to look at all the options and figure out what
works for them."

Residents of about 20 states are allowed to use gray-water
recycling systems in one form or another, according to AP.

Studies on the uses and effects of gray-water irrigation systems
are ongoing. For instance, Dr. Raul Cabrera, research
horticulturist at the Texas A&M AgriLife Research and
Extension Center in Uvalde, said in October that the recycling of gray
water in Texas from just household washing machines could save
around 400,000 acre feet of water a year, which equals about 8
percent of the state's annual water use.

Cabrera said his "research is particularly useful for
application in urban areas where as much as 50 percent of
household water is used for landscape irrigation." He added,
however, that very few Texas municipalities have addressed legal
installation of gray-water systems.